Product packaging is used to identify the contents of the package. Typically, a large quantity of boxes or bags is printed by a printing company and then shipped to a packaging facility where the packages are filled. Additional markings such as alphanumeric characters often are added to packages at the packaging facility using a low resolution printing process in order to track inventory or to provide manufacturing or expiration dates for the package contents. This type of package identification requires an additional printing or labeling step at the factory.
It is known to identify an individual item with a number that is specific to the item. Costly products such as television sets, computers and automobiles frequently have a unique serial number embossed or otherwise attached to the body of the product so that this number will be visible on the product during its useful life. Computer software is often sold with a unique identifying number or watermark inside the package in order to limit its reproduction beyond the scope of the intended license.
Courier services and film developers often use unique numerical sequences and/or bar codes that are preprinted on envelopes or package mailing labels in order to associate a particular envelope or package with a sender and a receiver at the time the package is addressed or shipped. This type of shipping procedure typically is used for packages containing unique items so that the packages can be located if they are lost.
U.S. Published Patent Application No. 2004/0007868 discloses a book covering with a unique identifier printed thereon and a method for printing a book covering using a printing press which has means for printing variable data. This document also discloses a method for printing a product package which includes printing a unique identifier on the package stock with a variable data printing apparatus. The variable data can be printed on-press along with non-variable data.
European Patent Application No. 554989-A1 (1993) is directed to a method of preparing packaging material with variable data printed thereon using an ion deposition or toner technology process. The non-variable data on the packaging material either can printed along with the variable data using ion deposition or toner technology, or in a separate printing process using a different type of printing process.